Borated-nitroalkyl-schiff base condensation products



United States Patent 3,328,463 BORATED-NITROALKYL-SCHIFF BASECONDENSATION PRODUCTS Richard J. Lee, Park Forest, 11]., assignor toStandard Oil Company, Chicago, 11]., a corporation of Indiana NoDrawing. Filed June 30, 1964, Ser. No. 379,339 2 Claims. (Cl. 260-566)This invention relates to aliphatic ketones. More particularly itrelates to nitro-ketone alkanes, their preparation, their use asintermediates in the preparation of ashless lubricant additives, andlubricants containing such additives.

The operation of the present day internal combustion engines inautomobiles, delivery trucks, taxicabs, police cars, etc. in so-calledstop and go city use results in severe demands for high dispersancy anddetergency as well as extreme oxidation stability and protection ofmetal parts to rust and corrosion. This severe demand on Inbricantadditives comes about by the accumulation of Water and partialcombustion products in the crankcase of the engines of the foregoingvehicles. Water and many of the partial combustion products result insludge formation which deposits on the valve train, pistons, pistonrings, oil screens and filters. The partial oxidation products, whendeposited on hot metal surfaces, form varnishes which impair theeiflcient operation of the engines. Many solutions to these severeperformance demands of city driving conditions have been sought, butwhile solutions to the dispersing of water, sludge and varnish-formingmaterials in the lubricant oil was of paramount importance, it was alsoof paramount importance that the additives to accomplish the dispersinghad to be thermally stable at high temperatures of continuous operationunder high speed highway and expressway traveling. Also with the adventof the recommendation by internal combustion engine manufacturers oflonger intervals between draining and replacement of crankcaselubricants, emphasis has also been directed at the protection ofbearings and other metal parts of the internal combustion enginesagainst corrosion, rust and wear. To further complicate the problems offormulating crankcase lubricants for the increasingly severe servicedemanded by the improved internal combustion engines, there was thealways present problem of compatibility of the other additives such asthe anti-wear, anti-corrosion, anti-rust and anti-oxidation additives.By adjustment of ratios of various additive materials, compatibilitycould be achieved at the sacrifice of bearing wear or bearing corrosion,rust inhibition and even oxidation stability.

A new method has been discovered for the preparation of nitro-ketonesfrom alkenes, which ketones are valuable intermediates in thepreparation of oil-soluble derivatives that are useful as ashlesslubricant additives.

In accordance with the present invention, an alkene is nitrated withnitrogen tetroxide under non-oxidizing conditions to form thecorresponding nitro-nitrito alkane. The nitro-nitrito alkane is thenhydrolyzed under alkaline conditions in the presence of a basic materialnonreactive with said alkane to the corresponding nitro-ketone alkane.

The nitration of the alkene is effected by treating the alkene undernon-oxidizing conditions with nitrogen tetroxide in an inert carrier gassuch as carbon dioxide or nitrogen at a temperature of from about 100 toabout 250 F. until absorption of the nitrogen tetroxide ceases. Thenitration is preferably conducted in an inert solvent. The amount ofnitrogen tetroxide used will be about one mole per mole of unsaturationin the alkene. The nitrated product is substantially pure nit-ro-nitritoalkane.

Any olefinic material containing at least one ethylenically unsaturatedsite can be treated in accordance with the present invention. Monoandpolyolefins can be converted to their corresponding nitro-ketonessubstantially quantitatively. Homopolymers of propene and butene havingan average molecular weight in the range of from about 300 to 60,000 areespecially useful products for the preparation of oil-solublenitro-ketones that can be further reacted to form ashless lubricantadditives.

The alkaline hydrolysis of the nitro-nitrito alkane can be effected bythe addition of a concentrated aqueous solution of basic material,non-reactive with the nitro-nitrito alkane thereto, and reacting theresultant mixture at reflux temperatures. Basic materials that can beused include quaternary ammonium hydroxides, polyamines that formquaternary ammonium hydroxides in situ such as diethylenetriamine, andinorganic bases such as barium hydroxide and calcium hydroxide.Temperatures may range from about 20 to about C. for a period of timesuflicient to convert the nitrito group to the keto group. Hydrolysis isgenerally complete when evolution of gas ceases.

The nitro-ketone alkanes containing at least 6 carbon atoms areparticularly useful for conversion to ashless lubricant additives thatimpart detergency to liquid lubricating oils. A particular effectiveclass of nitro-ketone alkanes are those derived from viscous polypropeneand polybutene having an average molecular weight in the range of fromabout 300 to about 2,000.

Reaction of the nitro-ketone alkanes with a polyamine having the formulaH N(RNH) H wherein R is C alkylene and x is 1 to 8, forms anitro-Schiifs base condensation reaction product. Illustration of thepolyamines are ethylene diamine, diethylene triamine, triethylenetetramine, tetraethylene pentamine, propylene diamine, butylene diamine,etc. The condensation of the nitro-ketone alkane and polyamine isconducted at temperatures of from about 200 to 320 F. in the presence ofa catalytic amount of an acid catalyst such as concentrated sulfuricacid. The molar proportion of the reactants is from about 2 to 4 molesof the alkane per mole of polyamine. The polyamine is preferably inslight excess to assure complete reaction with the keto groups in thenitro-ketone alkane.

The nitro-Schiifs base condensation product is then borated with boricacid or boric anhydride using about 3 moles equivalent boric acid permole of basic nitrogen in the condensation product to provide nitrogento boron ratio of about 3:1. The boration is conducted at temperaturesof from about 200 to 300 F. The borated condensation reaction product isa valuable lubricating oil detergent.

Illustrative of the invention are the following examples:

EXAMPLE I A viscous polybutene having an average molecular weight ofabout 860 was dissolved in heptane in a 3-necked flask equipped with astirrer and gas distributor, and reflux condenser. To this solutionnitrogen tetra-oxide was introduced in carbon dioxide carrier gas at therate of 2 cubic feet per hour at reflux temperatures, about F., for aperiod of 16 hours. Infrared analysis of the reaction product indicatedsubstantially complete conversion of the polybutene polymer to thecorresponding nitro-nitrito alkane.

EXAMPLE II Basic hydrolysis of a portion of the nitro-nitrito reactionproduct of Example I was conducted by treating said product with anequimolar amount of a concentrated aqueous solution of calcium hydroxideat reflux temperatures for 4 hours. Infrared analysis of the resultantreaction product indicated substantially complete conversion of thenitro-nitrito product to the corresponding nitro-ketone.

3 EXAMPLE III To 450 grams of the nitration product of Example I wasadded a concentrated aqueous solution of 25 grams of diethylenetriamine.The resultant mixture was then reacted at reflux temperature for 3hours. The resultant reaction mixture was separated on a silica gelcolumn and a yield of 70 percent of the corresponding pure nitroketonewas obtained.

EXAMPLE IV To 3 moles of the nitro-ketone product of Example II wasadded /3 mole of tretraethylenepentamine and 2 ml. of concentratedsulfuric acid as catalyst. The reaction mixture was then heated at 270F. for 12 hours. Thereafter, 200 grams of boric acid was added to thereaction mixture and the mixture heated at 300 F. for 12 hours. Analysisof the borated reaction product showed that it contained 1.27% nitrogenand 0.42% boron. Analysis of the condensation reaction product of thenitro-ketone and the amine by infrared showed the formation of thenitro-Schifis 'base reaction product.

The herein described borated reaction products are particularly suitablefor use in amounts of from about 0.1 to about 10 weight percent asashless addition agents for lubricating oils.

EXAMPLE V To a SAE 20 petroleum lubricating oil containing 1.2 weightpercent of zinc dialkyldithiophosphate as an antioxidation, anti-wearadditive there was added 2 weight ercent of the borated product ofExample IV. The resultant lubricating oil composition was tested in theLincoln MS Test Sequence V, to evaluate the low temperature dispersancycharacteristics of the oil. The results obtained are:

Sludge 33 Varnish 38 Piston varn. 7.2 Oil ring plugging 22 Oil screenplugging 5 This example illustrates that the borated products preparedin accordance with this invention exhibit excellent low temperaturedisperancy in lubricating oils.

Suitable lubricating base oils are hydrocarbon oils, e.g., petroleumoils, synthetic hydrocarbon lubricating oils such as those obtained bythe polymerization of hydrocarbons, and other synthetic lubricating oilssuch as alkylene oxide type oils, for example, the Ucon Oils,polycarboxylic acid ester-type oils such as esters of adipic acid,sebacic acid, azelaic acid, etc. and other synthetic lubricating oils.

While this invention has been described in connection with the use ofthe herein described additives and lubricant compositions, their use isnot limited thereto but the same can be used in products other thanlubricating oils, such as for example, fuel oils, insulating oils,greases, nondrying animal and vegetable oils, waxes, and asphalts.

Concentrates of a suitable oil base containing more than 10%, e.g. fromabout 15% to about or more, of the herein described derivatives, alone,or in combination with more than 10% of other additives, can be used forblending with other oils in proportions desired for the particularcondition or use to give a finished product containing from about 0.1 toabout 10 weight percent of the described derivative.

Lubricant composition containing the herein described derivatives cancontain other addition agents such as for example, antioxidants, pourpoint depressors, V.I. improvers, etc.

I claim:

1. The oil-soluble lubricant additive which comprises the reactionproduct obtained by condensing an aliphatic hydrocarbon nitro-ketonecontaining at least 6 carbon atoms with a primary polyamine having theformula H N(RHN) H wherein R is C alkylene and x is 1 to 8 in thepresence of a catalytic amount of an acid catalyst to form a reactionmixture containing the condensation product of said ketone and saidamine; then borating said reaction mixture with a member of the groupconsisting of boric acid and boric anhydride to provide borated reactionproduct containing ratio of nitrogen to boron of from 1 to 4:1.

2. The additive of claim 1 wherein said nitro-ketone is derived frompolybutene having a molecular Weight of about 860, said polyamine istetraethylenepentamine, said acid catalyst is sulfuric acid, and theratio of nitrogen boron is 3:1.

No references cited.

CHARLES B. PARKER, Primary Examiner.

ROBERT V. HINES, Assistant Examiner.

1. THE OIL-SOLUBEL LUBRICANT ADDITIVE WHICH COMPRISES THE REACTIONPRODUCT OBTAINED BY CONDENSING AN ALIPHATIC HYDROCARBON NITRO-KETONECONTAINING AT LEAST 6 CARBON ATOMS WITH A PRIMARY POLYMAINE HAVING THEFORMULA H2N(RHN)XH WHEREIN R IS C2-8 ALKYLENE AND X IS 1 TO 8 IN THEPRESENCE OF A CATALYTIC AMOUNT OF AN ACID CATALYST TO FORM A RECTIONMIXTURE CONTAINING THE CONDENSATION PRODUCT OF SAID KETONE AND SAIDAMINE; THEN BORATING SAID REACTION MIXTURE WITH A MEMBER OF THE GROUPCONSISTING OF BORIC ACID AND BORIC ANHYDRIDE TO PROVIDE BORATED REACTIONPRODUCT CONTAINING RATIO OF NITROGEN TO BORON OF FROM 1 TO 4:1.